/** Local implementation of the SHA1 hashing scheme
 *
 * SHA-1 in C 100% Public Domain
 *
 * @file src/lib/util/sha1.c
 *
 * @author Steve Reid (steve@edmweb.com)
 */
RCSID("$Id: 0bcccca9037e19df3bb39d453cc44e9107c626dd $")

#include <freeradius-devel/util/sha1.h>


#ifndef WITH_OPENSSL_SHA1
#  define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */

#  define blk0(i) (block->l[i] = htonl(block->l[i]))

#  define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#  define R0(v,w,x,y,z,i) do { z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30); } while (0)
#  define R1(v,w,x,y,z,i) do { z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30); } while (0)
#  define R2(v,w,x,y,z,i) do { z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30); } while (0)
#  define R3(v,w,x,y,z,i) do { z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30); } while (0)
#  define R4(v,w,x,y,z,i) do { z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30); } while (0)


/* Hash a single 512-bit block. This is the core of the algorithm. */

void fr_sha1_transform(uint32_t state[static 5], uint8_t const buffer[static 64])
{
	uint32_t a, b, c, d, e;
	typedef union {
		uint8_t c[64];
		uint32_t l[16];
	} CHAR64LONG16;
	CHAR64LONG16 *block;
	uint8_t workspace[64];

	block = (CHAR64LONG16*)workspace;
	memcpy(block, buffer, 64);

	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];

	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
	R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
	R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
	R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
	R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
	R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
	R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
	R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
	R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
	R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
	R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
	R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
	R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
	R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
	R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
	R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
	R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
	R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
	R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
	R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);

	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;

#  ifndef STATIC_ANALYZER
	/* Wipe variables */
	a = b = c = d = e = 0;
#  endif
}


/* fr_sha1_init - Initialize new context */

void fr_sha1_init(fr_sha1_ctx* context)
{
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}

/* Run your data through this. */
void fr_sha1_update(fr_sha1_ctx *context, uint8_t const *in, size_t len)
{
	unsigned int i, j;

	/*
	 *	If len == 0, there's nothing to do:
	 *	First, len == 0 impolies len * 8 == 0, so the contents of
	 *	context->count wouldn't change.
	 *	j by construction is <= 63, so if len == 0, j + len == j <= 63, and
	 *	i would be set to 0 and the final memcpy() would "copy" 0
	 *	bytes, so the contents of context->buffer wouldn't change either.
	 */
	if (len == 0) return;

	j = (context->count[0] >> 3) & 63;
	if ((context->count[0] += len << 3) < (len << 3)) {
		context->count[1]++;
	}

	context->count[1] += (len >> 29);
	if ((j + len) > 63) {
		memcpy(&context->buffer[j], in, (i = 64-j));
		fr_sha1_transform(context->state, context->buffer);
		for ( ; i + 63 < len; i += 64) {
			fr_sha1_transform(context->state, &in[i]);
		}
		j = 0;
	} else {
		i = 0;
	}
	memcpy(&context->buffer[j], &in[i], len - i);
}


/* Add padding and return the message digest. */

void fr_sha1_final(uint8_t digest[static SHA1_DIGEST_LENGTH], fr_sha1_ctx *context)
{
	uint32_t i, j;
	uint8_t finalcount[8];

	for (i = 0; i < 8; i++) {
		finalcount[i] = (uint8_t)((context->count[(i >= 4 ? 0 : 1)] >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
	}

	fr_sha1_update(context, (unsigned char const *) "\200", 1);

	while ((context->count[0] & 504) != 448) {
		fr_sha1_update(context, (unsigned char const *) "\0", 1);
	}
	fr_sha1_update(context, finalcount, 8);  /* Should cause a fr_sha1_transform() */
	for (i = 0; i < 20; i++) {
		digest[i] = (uint8_t)((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
	}

#  ifndef STATIC_ANALYZER
	/* Wipe variables */
	i = j = 0;
	memset(context->buffer, 0, 64);
	memset(context->state, 0, 20);
	memset(context->count, 0, 8);
	memset(&finalcount, 0, 8);
#  endif

#  ifdef SHA1HANDSOFF  /* make fr_sha1_transform overwrite it's own static vars */
	fr_sha1_transform(context->state, context->buffer);
#  endif
}

void fr_sha1_final_no_len(uint8_t digest[static SHA1_DIGEST_LENGTH], fr_sha1_ctx *context)
{
	uint32_t i, j;

	for (i = 0; i < 20; i++) {
		digest[i] = (uint8_t)((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
	}

#  ifndef STATIC_ANALYZER
	/* Wipe variables */
	i = j = 0;
	memset(context->buffer, 0, 64);
	memset(context->state, 0, 20);
	memset(context->count, 0, 8);
#  endif

#  ifdef SHA1HANDSOFF  /* make fr_sha1_transform overwrite it's own static vars */
	fr_sha1_transform(context->state, context->buffer);
#  endif
}
#endif
